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| United States Patent |
5,722,514
|
|
Kiyokawa
|
March 3, 1998
|
Tray installation rack for test handler
Abstract
A tray installation rack is used for a test handler to install therein a
plurality of trays each of which has a large number of IC devices to be
tested. The tray installation rack includes, a main base fixed to the test
handler, a slide base slidably mounted on the main base and has a floor
for receiving the trays thereon, a pair of tray guide bars perpendicularly
mounted on the slide base to meet two adjacent sides of the trays for
limiting movements of the trays in two horizontal directions, a pair of
tray adjust bars slidably provided on the slide base to press the trays
against the pair of guide bars in the two horizontal directions, an
elevator provided on the test handler to lift the trays in a vertical
direction in the tray installation rack until an uppermost tray exceeds
top ends of the tray guide bars, a pair of tray pushers provided at top
portions of the tray adjust bars, and tray standard members mounted on the
main base at immediately above the top ends of the tray guide bars to
restrict movements of the uppermost tray in the two horizontal directions,
wherein the uppermost tray is positioned when the uppermost tray is
pressed by the tray pushers against the tray standard members.
| Inventors:
|
Kiyokawa; Toshiyuki (Kuki, JP)
|
| Assignee:
|
Advantest Corp. (Tokyo, JP)
|
| Appl. No.:
|
636269 |
| Filed:
|
April 26, 1996 |
Foreign Application Priority Data
| Current U.S. Class: |
187/270; 187/240 |
| Intern'l Class: |
B66B 009/02 |
| Field of Search: |
187/240,243,244,270,271,406,414
|
References Cited
Attorney, Agent or Firm: Muramatsu & Associates
Claims
What is claimed is:
1. A tray installment rack for a test handler to install therein a
plurality of trays each of which has a large number of IC devices to be
tested, comprising:
a main base fixed to said test handler;
a slide base slidably mounted on said main base and has a floor for
receiving said trays thereon;
a pair of tray guide bars perpendicularly mounted on said slide base to
meet two adjacent sides of each of said trays for limiting movements of
said trays in two horizontal directions;
a pair of tray adjust bars slidably provided on said slide base to press
said trays against said pair of guide bars in said two horizontal
directions;
an elevator provided on said test handler to lift said trays in a vertical
direction in said tray installation rack until an uppermost tray exceeds
top ends of said tray guide bars;
a pair of tray pushers provided at top portions of said tray adjust bars;
and
tray standard members mounted on said main base at immediately above said
top ends of said tray guide bars to restrict movements of said uppermost
tray in said two horizontal directions;
wherein said uppermost tray is positioned when said uppermost tray is
pressed by said tray pushers against said tray standard members.
2. A tray installation rack as defined in claim 1, wherein said trays in
said tray installation rack are positioned by said tray guide bars when
pressed by said tray adjust bars against said tray guide bars in said two
horizontal directions while said uppermost tray is positioned by said tray
standard members when pressed by said tray pushers against said tray
standard members in said two horizontal directions.
3. A tray installation rack as defined in claim 1, wherein said tray
installation rack further includes a slide pack at a lower portion of said
slide base so as to allow a slidable movement of said tray installation
rack in a horizontal direction on said test handler.
4. A tray installation rack as defined in claim 3, wherein tray rack guide
rails are provided on said main base of said test handler, said tray rack
guide rails interact with said slide pack to promote said slidable
movement of said tray installation rack.
5. A tray installation rack as defined in claim 1, wherein said elevator is
mounted on said main base of said test handler, said slide base has an
opening on said floor to allow an up and down movement of said elevator
for lifting said trays.
6. A tray installation rack as defined in claim 1, wherein said slide base
slidably move on said test handler to a position apart from said elevator
and said tray standard members so as to secure easy loading and unloading
of trays for said tray installation rack.
7. A tray installation rack as defined in claim 1, wherein said elevator
moves in said vertical direction when guided by a linear guide.
8. A tray installation rack as defined in claim 1, wherein said tray
pushers are driven by air cylinders provided with compressed air.
9. A tray installation rack as defined in claim 1, wherein said tray
pushers are made of an elastic material.
Description
FIELD OF THE INVENTION
This invention relates to a tray installation rack to be incorporated in a
test handler for installing a plurality of trays carrying IC devices to be
tested, and more particularly, to a tray installation rack on the test
handler for accurately positioning different sizes of trays having IC
devices to be tested and assuring an easy and safe work of loading and
unloading the trays for the test handler.
BACKGROUND OF THE INVENTION
In testing IC devices, an automatic test handler is frequently used in
combination with an IC tester to automatically provides IC devices (DUT)
to be tested to a test position (test head) of the IC tester. There are
generally two types of test handlers, a self-drop type handler wherein the
IC devices to be tested are transferred in a vertical direction with their
own gravity and a tray type handler wherein IC devices aligned on a tray
are transferred in a horizontal direction to the test position either
directly or via a test tray.
In a typical tray type test handler, IC devices to be tested are aligned on
a tray which is sometimes called a customer tray provided by manufacturers
of the IC devices. The size of the tray varies depending on the type of IC
devices and the manufacture of the IC devices.
A plurality of such trays are installed in a tray installation rack prior
to the testing. During the testing, the IC devices on the trays are
removed from the tray and loaded on a test by a pick and place mechanism
of the test handler. The test tray is specially made for the test handler
to carry the IC devices to the test head of the IC tester where the IC
devices are tested. Alternatively, the IC devices to be tested are
transferred directly to the test head by the pick and place mechanism of
the test handler. The IC devices are sorted based on the test result. This
invention relates to such a tray installation rack to be used in such a
tray type test handler.
As noted above, a tray installation rack of a tray type test handler
involves processes of placing a number of trays containing IC devices to
be tested in a container like portion of the tray installation rack,
providing the IC devices automatically to an IC test system by replacing
the IC devices on the trays to the test trays. During the processes, each
tray is lifted by an elevator mechanism provided in the tray installation
rack and the IC devices at the top position of the tray are transferred to
the test tray by the pick and place mechanism of the test handler.
Therefore, the tray installation rack is required to have a precise
positioning ability to accurately shift the trays so that the IC devices
are transferred to the test tray without an error. Further, the tray
installation rack is required to safely and efficiently load and unload a
large number of trays before and after the testing. Since the size of the
tray varies, the tray installation rack needs to have a mechanism for
positioning such differently sized trays to accommodate various type of
trays and IC devices.
FIGS. 3-5 show a first example of conventional tray installation rack to be
used in a test handler. This example is a tray installation rack designed
with the main purpose of precise positioning the trays.
FIG. 3 is a perspective view and FIG. 4 is a side view of the tray
installation rack. The tray installation rack of FIGS. 3-5 include a main
base 80, adjustment bars 25, tray pushers 26, an elevator 35, linear
guides 45, a gear 75 and a linear head 76. A plurality of trays 90 are
stacked in a container like portion formed by the main base 80 and the
adjustment bars 25 as shown in FIGS. 3 and 4.
Although not shown, a large number of IC devices to be tested are mounted
on each tray 90. The test handler system picks up these IC devices and
transfers and places them on the test trays or a test socket of the test
head. The test trays horizontally move in the test handler to the test
head of the IC test system whereby electrical testing for the IC devices
is performed. Numerous trays 90 are piled up and stored in the tray
installation rack. The trays 90 are lifted to a predetermined position by
the elevator 35. The associated mechanism of the linear guides 45, the
gear 75 and the linear head 76 are provided to accurately drive the
elevator 35 in the vertical direction.
As noted above, according to the kind of IC devices, there are several
trays with different sizes. In order to handle various sizes of trays, the
tray installation rack is provided with a positioning system formed of the
main base 80, adjustment bars 25 and the tray pushers 26 to determine the
position of the trays in X and Y directions. It should be noted that
although the tray installation rack can accommodated difference sizes of
trays, the same trays are installed in the tray installation rack for each
test. In other words, differently sized trays are not installed together
in the tray installation rack.
The main base 80 is fixedly provided on the test handler to determine the
positioning reference of the test handler system. As shown in FIG. 3, the
main base 80 has a floor and X and Y walls. The X and Y walls limit the
movement of the trays 90 in the X and Y directions. The trays 90 are
placed at the corner formed by the X and Y walls of the main base 80 to
determined the position in the X direction and Y direction of the test
handler. For doing this, the trays 90 are pressed toward the X and Y
directions by the tray adjust bars 25 and the tray pushers 26.
In general, the bigger the elevator 35 for lifting the trays 90, the easier
it becomes to secure the horizontal position of the trays 90. FIG. 5 is a
plan view of the tray installation rack including the elevator 35 which
loads the trays 90. The horizontal surface (floor) of the elevator 35
which lifts the tray 90 is structured to be wide enough to accommodate the
largest tray except for the portion in which the tray adjust bars 25 move
back and forth. Hence, it has the surface defined by the pints a, b, c, d,
e, f, g, h, i, j, k, l, as shown by the hatched lines excluding the area
defined by the points d, e, f, g and i, j, k, l in which the movement of
the tray adjust bars 25 is secured.
The tray adjust bars 25 are arranged so that both bars can move in the X
and Y directions, respectively, until reaching the minimum tray size.
Thus, the minimum tray size is determined by the X and Y walls (upper and
right sides of FIG. 5) and the two surfaces of the tray adjust bars 25
facing the X and Y walls. The rectangular surface defined by the points a,
b, c, h of the elevator 35 has the area that can cover the maximum tray
size. Thus, even if the trays are with different sizes, the trays 90 are
always maintained horizontally because the elevator 35 floor has a
sufficient space to receive the trays.
To provide the trays 90 at a position suitable for picking the IC devices
to be tested and placing them on the test tray or directly on the test
head, the tray 90 is lifted or lowered to a desired position by the
elevator 35 by the following operation.
The linear head 76 is connected to the elevator floor to drive the elevator
35 in a vertical direction. The elevator 35 moves in the vertical
direction by the rotation of the gear 75 which engages with the linear
head 76. The linear guides 45 are provided to guide the movement of the
elevator 35 so as to maintain the horizontal plane of the elevator 35
during the movement.
The tray pushers 26 are provided at the upper part of the tray adjustment
bars 25 to press the top tray 90 which is lifted to the predetermined
height. The precise positioning for the top tray 90 is necessary because
the IC devices on the top tray 90 have to be unloaded by a pick and place
mechanism or a robot hand of the test handler. The tray pushers 26 press
the top tray 90 against the X and Y walls of the main base 80 to
accurately positioning the tray 90 as shown in FIG. 4. The tray 90 is thus
fixed to the walls of the main base 80, and thus accurately positioned to
avoid the error in the operation of picking the IC devices by the handler
system.
To improve a test efficiency, a large number of trays 90 are installed in
the tray rack to test a large number of IC devices by the test handler.
Loading and unloading the trays 90 in the tray rack are usually performed
by a manual labor before and after the test.
In the foregoing example, the tray 90 is fixed to the position in the main
base 80 of the handler fairly accurately since the position of the tray 90
is determined by the walls of the main base 80 when pressed by the tray
pusher 26. Namely, since the main base 80 is integrally or fixedly provide
on the test handler, the relative positioning between the test handler and
the trays 90 are achieved with high accuracy by the arrangement of FIGS.
3-5.
However, the loading and unloading of the trays 90 to and from the tray
installation rack is proceeded by human workers. Further, since moving
parts of the handler, such as the pick and place mechanism, are provided
at the upper position of the tray installation rack, an enough space for
loading and unloading the large number of trays by the human workers is
not available.
FIGS. 6 and 7 show a second example of a conventional tray installation
rack. This tray installation rack is primarily designed to ease the
loading and unloading works of the trays by providing a mechanism for
moving the tray installation rack in a horizontal direction on the test
handler.
FIG. 6 is a perspective view while FIG. 7 is a side view of the tray
installation rack. Tray installment rack of FIGS. 6 and 7 includes a slide
base 5 having slide packs 6, and tray guide bars 15 for positioning the
trays 90. As in the example of FIGS. 3-5, the tray rack further includes
the adjustment bars 25 and the tray pushers 26. The slide base 5 is
mounted on tray rack guide rails 8 provided on the test handler. The slide
base 5 serves as a floor for stacking the trays 90 as well as to form a
sliding mechanism for horizontally slide on the test handler along the
tray rack guide rails 8. A plurality of trays 90 are piled up on the floor
of the slide base 5. To accommodate the difference of size, the trays 90
are pressed by the adjustment bars 25 toward the tray guides 15 which form
walls to limit the movement of the trays 90 in the X and Y directions.
Similar to the example of FIGS. 3-5, the elevator 35, the linear guides 45,
the gear 75 and the linear head 76 are also provided. The trays 90 are
lifted to a predetermined position by the elevator 35 so that the tray 90
at the top position is accessed by a pick and place mechanism or a robot
hand to replace the IC devices to the test handler as mentioned above. The
elevator 35 includes the linear guides 45, the gear 75 and the linear head
76 to accurately drive the elevator 35 in the up and down direction. The
elevator 35, the linear guides 45, the gear 75, the linear head 76, and
the tray rack guide rails 8 are fixedly provided on the main base 80.
The example of FIGS. 6 and 7 is provided with the slide pack 6 for pulling
out and pushing in the slide base 5 on the test handler to allow a
horizontal movement of the tray rack on the handler. Namely, the slide
base 5 is guided by the tray rack guide rails 8 via the slide pack 6 in
the direction shown by the arrow on the test handler. The slide pack 6 is
provided to allow a smooth movement of the slide base 5 along the tray
rack guide rails 8.
Thus, the trays 90 can be replaced when the tray installation rack is
pulled out from the position where the elevator is provided. Although not
shown, the test handler has, on the upper part of the elevator and the
tray installation rack, a mechanism for removing the IC devices from the
tray, such as the pick and place mechanism. By shifting the horizontal
position of the tray installation rack from the pick and place, a larger
space at the top of the tray installation rack is available which makes
the tray replacement easy and smooth. Further, since the moving mechanism
or components do not exist around the tray installation rack at this
position, the tray replacement work is undertaken safely.
The situation where the uppermost tray 90 is vertically lifted to the
predetermined position for removing the IC devices to be tested is shown
in FIG. 7. The tray guide bars 15 and the tray adjust bars 25 are provided
on the slide base 5 to serve as determining the position of the uppermost
tray 90. The tray pushers 26 further serve to secure the precise position
of the tray 90 by pressing the tray against the tray guide bars 15.
However, in this example, since the positioning of the tray 90 is made with
respect to the tray guide bars 15 which are not directly attached to the
test handler, such positioning is not necessarily accurate with respect to
the test handler, especially with respect to the pick and place mechanism
of the test handler. Moreover, because the slide pack 6 is to allow a
slidable movement to the tray installation rack, there required subtle
gaps between the test handler, i.e., the tray rack guide rails 8 and the
slide base 5. Thus, the precise positioning is difficult to attain with
respect to the handler, and an error X such as shown in FIG. 7 is
unavoidable in the positioning of the tray 90 with respect to the main
base 80 or the pick and place mechanism of the test handler.
As note above, in the example of FIGS. 6 and 7, since the positioning
standard for the slide base is not directly provided to the test handler,
it is not possible to precisely and accurately position the tray
installation rack and thus the trays 90 with respect to the test handler.
To realize the precise positioning of the tray installation rack, an
expensive linear motion guide, for example, has to be used instead of the
slide pack of FIGS. 6 and 7 for interfacing the slide base 5 and the test
handler.
SUMMARY OF THE INVENTION
It is therefore, an object of the present invention to provide a tray
installation rack which is capable of precisely and accurately positioning
a tray at the top of the tray installation rack with respect to a test
handler.
It is another object of the present invention to provide a tray
installation rack which is capable of easily and safely loading and
unloading the trays before and after the test of the IC devices.
It is a further object of the present invention to provide a tray
installation rack which is capable of precisely and accurately positioning
a tray at the top of the tray installation rack with respect to a test
handler without incorporating an expensive mechanism.
It is a further object of the present invention to provide a tray
installation rack which is capable of sliding on the test handler for
loading and unloading a large number of trays and accurately positioning
the trays with respect to the test handler.
In order to accomplish the task, the length of the tray guide bars in the
present invention are shortened with respect to the length of the tray
adjust bars compared with the conventional example of FIGS. 6 and 7. Over
the top of the tray guide bars, tray standard bars are arranged on a main
base of the test handler system.
When the tray is lifted to the uppermost level of the tray installation
rack by an elevator, the uppermost tray that has been positioned by the
tray guide bar, is then positioned by the tray standard bars. A tray
pusher is installed on each tray adjust bar in the X and Y directions at
the level corresponding to the height of the tray standard bar. The
uppermost tray is pressed against the tray standard bar by the tray
pusher.
As result of which, the uppermost tray is precisely positioned with respect
to the test handler because the tray standard bars are fixed to the main
base of the test handler. The tray installation rack can be pulled out
together with the tray, and the trays can be replaced when the tray
installation rack is pulled out and thus an enough space is available
around the tray installation rack.
The tray installation rack of the present invention is used for a test
handler to install therein a plurality of trays each of which has a large
number of IC devices to be tested. The tray installation rack includes: a
main base fixed to the test handler; a slide base slidably mounted on the
main base and has a floor for receiving the trays thereon; a pair of tray
guide bars perpendicularly mounted on the slide base to meet two adjacent
sides of each of the trays for limiting movements of the trays in two
horizontal directions; a pair of tray adjust bars slidably provided on the
slide base to press the trays against the pair of guide bars in the two
horizontal directions; an elevator provided on the test handler to lift
the trays in a vertical direction in the tray installation rack until an
uppermost tray exceeds top ends of the tray guide bars; a pair of tray
pushers provided at top portions of the tray adjust bars; and tray
standard members mounted on the main base at immediately above the top
ends of the tray guide bars to restrict movements of the uppermost tray in
the two horizontal directions; wherein the uppermost tray is positioned
when the uppermost tray is pressed by the tray pushers against the tray
standard members.
According to the present invention, the tray standard members (bars) are
provided in the X and Y directions of the main base of the handler system
which has a pick and place mechanism for removing the ID devices from the
tray and placing the IC devices on the test tray. When the tray is lifted
by the elevator to the level where the tray standard bars are provided,
the positioning function is transferred to the tray standard bars. Thus,
horizontal level of the tray is maintained by the elevator while the
positioning in the X and Y directions are precisely determined by the tray
standard bars when the tray is pressed by the tray pushers against the
tray standard bars.
Accordingly, problems involved in the conventional tray installation rack
are eliminated. For example, there was a problem in which the IC devices
on the tray are not in the accurate positions such that a suction inlet of
the pick and place mechanism cannot properly attract the IC devices. In
the other problem, the pick and place mechanism cannot accurately place
the IC devices that have been tested on the tray based on the test
results. These problems are solved in the present invention.
The tray installation of the present invention can be slidably movable
together with the trays 90 on the test handler. Hence, the trays can be
easily replaced when the tray installation rack is separated from the
elevator and pick and place mechanisms. Since the tray replacement, i.e.,
the loading and unloading, is taken place where an enough space is secured
around the tray installation rack and no moving mechanism exist proximate
to the tray rack, the exchange of the trays can be safely and efficiently
performed.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view showing an embodiment of the tray installation
rack for a test handler system according to the present invention.
FIG. 2 is a side view showing the tray installation rack of the present
invention shown in FIG. 1.
FIG. 3 is a perspective view showing a first example of conventional tray
installation rack.
FIG. 4 is a side view showing the first example of tray installation rack
of FIG. 3.
FIG. 5 is a plan view showing the first example of tray installation rack
of FIG. 3 including an elevator for lifting the trays.
FIG. 6 is a perspective view showing a second example of conventional tray
installation rack.
FIG. 7 is a side view showing the second example of tray installation rack
of FIG. 6.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The preferred embodiment of the present invention will be explained with
reference to the drawings. FIG. 1 and 2 explains the tray installment rack
of the present invention to be used for the test handler system. FIG. 1 is
a perspective view showing an embodiment of the tray installation rack for
the test handler system of the present invention. FIG. 2 is a side view
showing the tray installation rack of the present invention of FIG. 1. For
convenience and ease of description, the reference numerals used in FIGS.
1 and 2 correspond to the similar portions of the conventional tray rack
of FIGS. 6 and 7.
As shown in FIG. 1, the tray guide bars 15 for positioning the tray are
arranged in the X and Y directions while crossing together at 90 degrees
on the slide base 5. The slide base 5 serves as a floor on which a
plurality of trays 90 are stacked before and after the testing as shown in
FIG. 2. The slide base 5 has a large opening for the elevator 35 moving in
the vertical direction to place the top tray 90 at the position for
removing the IC devices therefrom. The tray adjust bars 25 fix the trays
90 by pushing them against the tray guide bars 15 in the X and Y
directions, which accommodate trays 90 of different sizes. Thus,
positioning for the tray guide bar 15 on the tray slide base 5 is
performed.
At the slide base 5, the slide pack 6 which works as promoting the movement
of the slide base 5 along the tray rack guide rails 8. Thus, the slide
base 5 can be horizontally pulled out to the front of the test handler
where the trays 90 can be loaded on or unloaded from the tray installation
rack.
Similar to the description made with reference to FIG. 5, the horizontal
surface of the elevator 35 which lifts the trays 90 is widely formed to
receive the largest size trays 90 except for the area wherein the try
adjust bars 25 move toward the X and Y directions. Namely, as shown in
FIGS. 1 and 5, the elevator 35 has a surface area defined by a, b, c, d,
e, f, g, h, i, j, k, l in which areas defined by d-e-f-g and i-j-k-l are
excluded for allowing the movement of the tray adjust bars 25. Hence the
trays 90 can be aligned with reference to the tray guide bars 15
regardless of their size when pressed against the tray guide bars 15 while
the trays 90 can be vertically moved by the elevator 35.
In the present invention, for accurately positioning the tray 90 at the top
of the tray installation rack for picking the IC devices, the tray
standard bars 50-53 are provided in the X and Y directions on the main
base 80 of the test handler system. The tray standard bars 50-53
ultimately determine the position of the top tray 90 when the tray 90 is
pressed against the standard bars 50-53 by the tray pushers 26 provided at
the top portion of the tray adjust bars.
As explained above, the trays 90 are first positioned by the tray guide
bars 15 when pressed thereto by the tray adjust bars 25. Then, the trays
are lifted by the elevator 35 until the uppermost tray 90 comes to the
predetermined level of the tray installation rack. As shown in FIG. 2, the
length of the tray guide bars 15 are shorter compared with the tray adjust
bars 25. Immediately above the top of the tray guide bars 15, the tray
standard bars 50-53 are arranged in the X and Y directions. The tray
standard bars 50-53 are provided on the main base 80 rather than the slide
base 5 as shown in FIGS. 6 and 7.
Thus, when the top trays 90 are lifted by the elevator 35 and the top tray
90 reaches the predetermined upper level, the tray 90 which has been
positioned by the tray guide bars 15 is transferred to the positioning by
the tray standard bars 50-53. To meet the height of the tray standard bars
50-53, the tray pushers 26 are attached to the tray adjust bars 25 which
are movable in the X and Y directions. Thus, the uppermost tray 90 is
pressed against the tray standard bars 50-53 by the tray pushers 26. As a
result, the tray 90 is precisely positioned with respect to the test
handler because the tray standard bars 50-53 are integrally or fixedly
provided on the main base 80 of the test handler as noted above.
In this arrangement, the tray guide bars 15 only function to position the
tray 90 to a certain degree before the tray 90 is ultimately positioned by
the tray standard bars 50-53. Hence, the precise alignment of the tray
guide bars 15 or the slide base 5 is unnecessary, which does not require
to employ an expensive mechanism such as a linear motion guide.
The above tray standard bars 50-53 only need to secure the positioning the
trays with respect to the main base 80 of the test handler. Although four
tray standard bars are shown in the example of FIG. 1, only one tray
standard bar can be utilized for each of the X and Y directions facing the
tray adjust bar. Alternatively, three or more standard bars can be used
for each of the X and Y directions. The tray pushers 26 are provide with a
drive mechanism (not shown) such as an air cylinder to give a pressure to
the tray 90. The tray pushers 26 are preferably made of an elastic
material to flexibly press the tray 90.
As in the foregoing, according to the present invention, the tray standard
bars are provided in the X and Y directions of the main base of the
handler system which has the pick and place mechanism for removing the IC
devices from the tray and placing the IC devices on the test tray. When
the tray is lifted by the elevator to the level where the tray standard
bars are provided, the positioning function is transferred to the tray
standard bars. Thus, horizontal level of the tray is maintained by the
elevator while the positioning in the X and Y directions are precisely
determined by the tray standard bars when the tray is pressed by the tray
pushers against the tray standard bars.
Accordingly, problems involved in the conventional tray installation rack
are eliminated. For example, there was a problem in which the IC devices
on the tray are not in the accurate positions such that a suction inlet of
the pick and place mechanism cannot properly attract the IC devices. In
the other problem, the pick and place mechanism cannot accurately place
the IC devices that have been tested on the tray based on the test
results. These problems are solved in the present invention as in the
foregoing.
The tray installation of the present invention can be slidably movable
together with the trays 90 on the test handler. Hence, the trays can be
easily replaced when the tray installation rack is away from the elevator
and pick and place mechanisms. Since the tray replacement, i.e., the
loading and unloading, is taken place where the enough space is secured
around the tray installation rack and no moving mechanism exist proximate
to the tray rack, the exchange of the trays can be safely and efficiently
performed.
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